Process for shrinkproofing fibers with vinyl derivatives



United States Patent Ofiice 3,031,334 Patented Apr. 24, 1962 3,031,334 PROCESS FOR SHRINKPROOFING FIBERS WITH VINYL DERIVATIVES Harold P. Lundgren, Berkeley, and Clay E. Pardo, Jr.,

Albany, Calif., assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Original application Nov. 5, 1954, Ser. No. 467,247. Divided and this application Mar. 17, 1960, Ser. No. 19,977

2 Claims. (Cl. 117-55) (Granted under Title 35, U.S. Code (1952), sec. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, for all governmental purposes, throughout the world, With the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

" This application is a division of application bearing Serial No.- 467,247, filed November 5, 1954, now abandoned.

This invention relates to processes for shrinkproofing and feltproofing proteinous fibers, particularly wool. In particular the invention is concerned with procedures wherein the fiber is treated with a vinyl compound in the presence of a redox catalyst system whereby the vinyl compound is polymerized on the'fiber thus to produce a modified fiber which exhibits a marked resistance to shrinkage as compared with the original fiber. A particular aspect of the invention concerns the use of certain catalysts, i.e., a hydrazine salt, as the reducing agent in the redox system whereby to attain improved results, namely, a greater reduction in shrinkage for a given uptake of vinyl compound and a desirable Whitening of the fiber. Further objects and advantages of the invention will be obvious from the description herein.

It is well known that laundering causes severe shrinkage of woolen textiles. This technical disadvantage seriously restricts the applications of Wool in the textile industry and much research has been undertaken to modify the natural fiber to reduce its shrinkage properties. In general, treatments wherein Vinyl compounds, such as acrylonitrile, for example, are polymerized on the fiber have given the desired result of decreasing the shrinkage properties of wool. In these treatments the wool is subjected to the action of a polymerizable vinyl compound in the presence of a redo-x catalyst system. Such a system includes a reducing agent and an oxidizing agent, the interaction of these agents providing free radicals Which catalyze polymerization of the vinyl compound of the fiber. The oxidizing agent in the redox system is usually a peroxygen compound such as hydro gen peroxide. The reducing agent generally employed is a ferrous salt such as ferrous sulphate.

It has now been found that if a hydrazine salt is used as the reducing agent in the redox catalyst system greatly improved results are obtained. In the first place, the hydrazine salt exhibits an enhanced effect on the reduction of shrinkage so that when the hydrazine salt is so used a greater reduction in shrinkage properties is obtained with the same uptake of vinyl compound by the fiber. This of course is an impomant advantage in that it means that less vinyl compound need be incorporated into the fiber to obtain a product which is shrinkproof to the desired level. This in turn means that less damage to the hand of the textile Will be caused by the modification treatment. It is of course axiomatic that the less polymer is incorporated in the fiber-the more the fiber will retain its original and desirable properties of softness and other qualities which make up the hand of the textile. A second point to be emphasized is that the use of ferrous sulphate or other ferrous salt is generally detrimental to the color of the fiber. Thus metallic salts such as ferrous salts are strongly adsorbed by the fiber and even thorough washing will be unable to remove the last traces of the metal salt. As a result a staining or discoloration of the fiber will result, particularly by air oxidation of the ferrous compound to the more highly colored ferric compounds or by conventional laundering wherein deeply colored ferric hydroxide will be formed in the fiber. The net result of the use of ferrous sulphate is that even after prolonged and exhaustive washing the modified fiber will be less white than the original fiber. In the case of hydrazine salts this discoloration is not observed. On the contrary, it has been found that the fiber modified in the presence of hydrazine salts is even whiter than the original, unmodified fiber.

The process in accordance with this invention involves essentially treating the fiber with a vinyl compound in the presence of a redox catalyst system wherein the reducing agent in the catalyst system is a hydrazine salt.

As the substance which is polymerized on the fibers one may use any polymerizable vinyl compound, that is, generically a compound containing the radical CH CH Typical examples of compounds within the purview of the invention are:

Esters of the hypothetical vinyl alcohol, for instance, vinyl chloride, viny-l bromide, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl stearate, vinyl chloroacetate, vinyl trichloroacetate, and vinyl methoxyacetate.

Vinyl ethers, for instance, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, and cyclohexyl vinyl ether.

Vinyl ketones, for example, ethyl vinyl ketone and methyl vinyl ketone.

Acrylic acid esters, for instance, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, cyclohexyl acrylate, benzyl acrylate, and chlorobenzyl acrylate.

Esters of alpha-chloroacrylic acid, for instance, the methyl, ethyl, propyl, butyl, cyclohexyl, benzyl, and chlorobenzyl esters.

Esters of methacrylic acid, as for instance, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, and chlorobenzyl methacrylate.

Other acrylic compounds such as acrylonitrile, acrylic chloride, acrylamide, acrylalkylamides, acrylic anilide, N,N'-methylene bis acrylamide, acrylic acid, methacrylonitrile, methacrylic chloride, methacrylamide, methacrylalkylamides, methacrylic anilide, N,N-methylene bismethacrylamide, methacrylic acid. Derivatives of alphachloroacrylic acid such as the nitrile, chloride, amide, alkylarnides, anilide, and so forth.

Other vinyl compounds, for example, styrene, vinyl naphthalene, vinyl pyrrolidone, and divinyl benzene.

If desired, mixtures of the monomers may be applied to obtain formation of co-polymers on the fiber. Thus one may employ mixtures of monomers as exemplified by the following: vinyl chloride. and vinyl acetate; vinyl chloride and methyl methacrylate; acrylonitrile and acrylamide; acrylonitrile and vinyl pyrrolidone; styrene and acrylonitrile; acrylonitrile and divinyl benzene; ethyl methacrylate and acrylonitrile; N,N-methylene bis acrylamide or N,N'-methylene bis-methacrylamide and acrylonitrile; etc. Other selections of two or more monomers from the above examples would be obvious to those skilled in the art. Also, it is possible to employ other polymerizable monomers, for example, esters of maleic acid or itaconic acid, in conjunction with one or more of the vinyl monomers.

In the redox catalyst system, the reducing agent is a salt of hydrazine. The important feature is the presence of hydrazine; the acid moiety of the salt may be derived from any acid as for example hydrochloric, hydrobromic, sulphuric, sulphurous, phosphoric, acetic, benzoic, etc. The hydrazine may be completely or only partly salified by the acid. As the oxidizing agent in the redox system one may use such agents as hydrogen peroxide, barium peroxide, benzoyl peroxide, acetyl peroxide, tertiarybutyl hydroperoxide, alkali metal salts of tertiarybutyl hydroperoxide, alkali metal salts of per-acids such as per-acetic, per-benzoic, per-sulphuric, etc.

The vinyl monomer and redox system may be applied to the fiber in any of various ways. For instance, one technique involves first impregnating the fiber with a solution of the hydrazine salt. The hydrazine-containing fiber is then put into a bath containing the vinyl compound and the oxidizing agent whereby the vinyl compound will be polymerized on the fiber. If desired the sequence may be altered so that the fiber is first impregnated with the vinyl compound and one of the redox pair, for example, the hydrazine salt. The impregnated fiber is then placed in a bath containing the other redox catalyst (the oxidizing agent, in this case) whereby the vinyl compound will be polymerized n the fiber. Other variations of the sequence in which the reagents are applied will be obvious to those skilled in the part. Usually the vinyl compound and redox system are applied to the fiber in aqueous solution. It is obvious that where the vinyl compound selected is insoluble in water it can be applied in solution in a suitable solvent such as acetone, ethanol, carbon tetrachloride, benzene, etc. Further, where a surface-active agent is used (as noted hereinafter) the vinyl compound need not be dissolved in the aqueous system but can be emulsified therein by the action of the surface-active agent.

In treating the fiber with the solutions of the vinyl compound and the redox catalysts, it is preferred that the solution or solutions contain a wetting agent to enhance penetration of the reagents into the fiber. One may use for this purpose any of the agents which possess surfaceactive properties and which are useful in general wetting and detergent applications. Such agents are exemplified by soap, long-chain alkyl sodium sulphates or sulphonates, sodium alkyl benzene sulphonates, sodium alkyl naphthalene sulphonates, sodium alkyl phenol sulphonates, sodium alkyl toluene sulphonates, sodium dialkyl sulphosuccinates, sulphonated or sulphated esters or amides of high-molecular weight fatty acids, long-chain alkyl trimethyl ammonium chloride, bromide, or methosulphate, and so forth. There may also be used non-ionic surface active agents such as mannitol laurate, sorbitol laurate, and ethylene oxide reaction products with fatty acids, fatty alcohols, polyhydric alcohols, or with esters of polyhydric alcohols and high molecular weight fatty acids. In addition to enhancing the wetting of the fiber by the treatment solution, the surface-active agents can be employed to hold water-insoluble vinyl compounds in suspension or emulsion so that they will be effectively polymerized on the fibers.

The time of treatment of the fiber with the vinyl compound and the redox catalyst system may be varied in accordance with the concentration of the vinyl compound in the treating solution, the temperature, the polymerization properties of the selected vinyl compound, and the degree of modification of the fiber desired. In some cases a treatment time of 30 minutes is adequate to obtain a high degree of shrinkproofing; in other cases the time may have to be extended to several hours. The temperature of the treatment may be from about 20 to about C. Preferably to prevent damage to the fiber the temperature is maintained below 90 C. In the case of several vinyl compounds such as acrylonitrile., N,N'- methylene bis-acrylamide, and methyl methacrylate a temperature of around 60 C. is preferred as giving rapid polymerization without detriment to the tensile strength and other properties of the fiber. It is obvious that such treatment conditions as concentration of reagents, time and temperature of reaction are not critical but may be modified to suit individual circumstances without changing the basic nature of the present invention. In general the shrinkproofing effect will increase with increasing uptake of the vinyl reactant by the fiber, but not necessarily in linear proportion. As shown in the examples, with acrylonitrile and N,N'-methylene bis-acrylamide, uptakes on the order of 5 to 15% will virtually eliminate shrinkage. It is evident that higher or lower uptakes of the vinyl derivatives can be used depending on the degree of shrinkproofing desired. Usually it is preferred to limit the uptake to about 5 to 15% so that a high degree of shrinkproofing will be attained without impairment of the hand of the textile material.

The process of the present invention is applicable generically to proteinaceous fibers or their mixtures with other textile fibers whet-her the fibers are in such form or in the form of thread, yarn, sliver, knitted goods, woven goods, and so forth. The invention is particularly adapted to the treatment of wool but may also be applied to other proteinaceous fibers such as silk, fur, mohair, other fibers from fleece-bearing animals, synthetic fibers made from casein, zein, peanut proteins, keratins, etc.

The invention is further illustrated by the following examples.

EXAMPLE I A. Swatches of woolen cloth were immersed in an aqueous solution containing 0.5% hydrazine sulphate and 0.05% of sodium alkyl (C -C benzene sulphonate using about 35 parts of solution per part of wool. The cloth was then removed from the solution and centrifuged to remove excess liquid.

B. The hydrazine-impregnated swatches were then each immersed in an aqueous solution containing 3.5% acrylonitrile, 0.5% hydrogen peroxide, and 0.05% of sodium alkyl (C -C alkyl benzene sulphonate, using a wool to solution ratio of l to 50. The solutions were maintained at 60 C. and the cloth samples were kept therein for various lengths of time (as hereinafter specified). The samples were then removed, centrifuged to remove excess liquid, then washed thoroughly to remove unreacted materials.

C. The treated samples were subjected to analysis to determine the uptake by the fibers of the acrylonitrile. Samples of the treated cloth and a sample of the original, untreated cloth were subjected to a standard laundering technique and the area shrinkage of each sample was then determined. The conditions used and the results obtained are tabulated below:

Uptake of Area Time of acrylonishrinkage Sample treatment, trile, after launmmutes percent dering, percent Contr 45 l 30 2. 7 2B. 2 60 6. 7 13. 0 90 15. 6 8. 4 19.8 7. 7

It was also observed that all of the treated samples (1 to 4) were whiter than the untreated sample control).

Comparative Experiment The following experiment is not illustrative of the invention but is included to show the inferior results obtained wtllien ferrous sulphate is used in place of hydrazine sulp ate.

Swatches of woolen cloth were immersed in an aqueous solution containing 0.2% ferrous sulphate and 0.05 of sodium alkyl (C -C benzene sulphonate using about 35 parts of solution per part of wool. The cloth was then removed from the solution and centrifuged to remove excess liquid.

The ferrous sulphate-impregnated swatches were then each immersed in an aqueous solution containing 3.84% of acrylonitrile, 0.01% of hydrogen peroxide and 0.05% sodium alkyl (C -C1 benzene sulphonate, using a wool to solution ratio of 1 to 100. The solutions were maintained at 60 C. and the cloth samples were kept therein for various periods of time (as specified below). The samples were then removed from the solution and centrifuged to remove excess liquid then washed thoroughly to remove unreacted materials. The treated samples and a control (untreated sample) were then subjected to analysis and laundering as described in Example I. The conditions used and the results obtained are tabulated be- It was observed that all of the treated samples were brown in color whereas the untreated cloth (control) was white.

The advantages of hydrazine over ferrous sulphate are evident from a comparison of the above data and that set forth in Example I. For example, when proceeding in accordance with this invention, an uptake of 6.7% of acrylonitrile reduced shrinkage from 45% to 13%. On the other hand, when ferrous sulphate was used as the reducing agent, it required an acrylonitrile uptake of 19.9% to accomplish an equivalent reduction in shrinkage. In addition when hydrazine sulphate was used, the treated wool was whiter than the original wool; in the case of ferrous sulphate the wool was darkened by the treatment.

EXAMPLE II An aqueous solution containing 0.5% hydrazine sulphate and 0.05 of sodium alkyl (C -C benzene sulphonate was prepared. Swatches of woolen cloth were immersed in the solution then centrifuged to remove the excess liquid. The swatches were then each immersed in an aqueous solution containing N,N-methylene bisacrylamide (concentration specified below), 0.5% hydrogen peroxide, and 0.05% sodium alkyl (C -C benzene suiphonate. The solutions were maintained at 60 C. and the cloth samples were kept therein for various lengths of time (as specified below). The samples were then removed from the solution and centrifuged to remove excess liquid then washed thoroughly to remove unreacted materials. The treated samples were subjected to analysis to determine the uptake by the fibers of the amide. Samples of the treated cloth and a sample of the original, untreated cloth were subjected to a standard laundering technique and the area shrinkage of 6 each sample was then determined. The conditions used and the results obtained are tabulated below:

Concentration Uptake of Area 0! N,N-meth- Time oi N,N-methshrinkage Sample yleue bis acrylreaction, ylene bis after amide in treatminutes acrylamtde, laundering, ing bath, percent percent percent Control 45 0.3 4. 6 10.4 0.6 120 5. 4 9.0 1. 0 120 6. 4 9. 0 1.3 120 8.3 7. 7 2. 5 30 11.0 5.6 5.0 38 18.1 4. 9 5. 0 180 20. 6 2. 1

EXAMPLE III Swatches of woolen cloth were impregnated with hydrazine sulphate as set forth in Example I, part A.

The impregnated swatches were then treated with the following solutions using a wool to solution ratio of 1 to 35, a temperature of 60 and a reaction time of minutes:

( 1) Acrylamide g 0.5 Acrylonitrile ml 1.5 Hydrogen peroxide (30%) ml 1.16 Water ml 67 (2) Acrylonitrile ml 1.5 Vinyl pyrrolidnne ml 0.5 Hydrogen peroxide (30%) ml 1.16 Water ml 67 The treated samples were subjected to analysis and laundering as set forth above. The results are set forth below:

Area Uptake of shrinkage Sample Copoly'mer copolymer, after percent laundering, percent Control 37. 8 1 acrylamide-acrylonitrile. 12.8 5. 4 2 acrylonitrile-vinyl pyrro- 10. 3 6.6

lidone.

EXAMPLE IV Solution Ingredients Divinyl benzene, 2 ml.

Methyl acrylate, 2 m1.

Methyl acrylate, 2 ml. and acrylonitrile, 2 ml. Acrylic acid, 2 ml.

Styrene, 0.25 ml. and acrylonitrile, 1.75 ml.

Styrene, 0.5 ml. and acrylonitrile, 1.5 ml.

Styrene, 0.75 ml. and acrylonitrile, 1.3 ml.

Divinyl benzene, 0.25 ml. and acrylonitrile, 1.75 ml. Divinyl benzene and acrylonitrile, 1 ml. each. Ethyl methacrylate and acrylonitrile, 1. ml. each.

The results obtained are set forth below: 1. A process for shrinkproofing wool which comprises treating wool with acrylonitrile and acrylamide in the Area presence of a redox catalyst system wherein the reducing Sample Pol er P? 23 3 agent forsaid redox catalyst system is a hydrazine salt. ym polymer, launder- 5 2. A process for shrinkproofing wool which com- Percent i prises impregnating wool with a solution of a hydrazine salt, then impregnating the impregnated wool with a 35 solution containing acrylonitrile, acrylamide, and an oxi- 15.4 15.0 1 Methyl acrylate 7 4 0 dizmg agent which in con unct on with the hydrazine salt Mletthsilacrylate and acrylonitrile, 14.3 6.9 forms a redox catalyst system.

0 sf fi "iit'i"i"ii" i" ii;

en an a 1 ggg g g gl gg t g1 g 1 31 7 g g References C ted in the file of th s patent yrenean 81 011 0 Dilvtinlbenze 1g and zi ri lonitrile, 14.6 18.8 15 UNITED STA1 Es PATENTS 0 Dlvnyllbenzeneandacrylonitrile, 19.9 15.3 2, ,948 stalllngs Feb. 6, 1945 0 2406454 Charlton et a]. Aug. 27 1946 Eth lmetha latea (lac l0 14.7 15.2

triie,1to1. H W m 2,467,234 Sargent et al. Apr. 12, 1949 V 2,727,019 Melarned Dec. 13, 1955 Having thus described the invention, what is claimed 20 2,975,077 Coe Mar. 14, 1961 

1. A PROCESS FOR SHRINKPROOFING WOOL WHICH COMPRISES TREATING WOOL WITH ACRYLONITRILE AND ACRYLAMIDE IN THE PRESENCE OF A REDOX CATALYST SYSTEM WHEREIN THE REDUCING AGENT FOR SAID REDOX CATALYST SYSTEM IS A HYDRAZINE SALT. 